Question about Eldest's End objective

If you choose to screw over the coral and save the nacreous outcast, trapping the coral in consciousness for all eternity, does that count as witnessing the coral dying?

According to the wiki, no. You need “Principles End: Principality = 200” which you only get by winning the final chess match. Losing sets the quality to 100.

Ah, thanks. So they make you choose which father’s bones objective you can fulfill here. I’m deciding whether to complete the curator’s quest on this run, and if not things don’t look good for the outcast.

If you are close to finishing, the Curator’s quest is pretty good. You get a lot of Captivating Treasures out of it, which you can turn into Heirlooms for future captains to use. Maybe for the Wealth ending?